But that's what I mean - how can people avoid the photographer when you don't know who it is?

Because photography does not have any laws. Most people agree that there is a set of things you can do to make better photographs, but that does not mean you can say in public that someone is a swindler as nothing is fixed by law.
Like I Loco wrote in his thread: "it's up to them to do their homework." If people buy, then it is their own choice or problem, not that of the seller.

You cannot say "X" is a bad photographer without riskinng having to come to court for slander.

Besides: there are many like him ,and when I read the article this thread is about, I interpret it as being against a practice of people, not an individual person.

If you live in the same town/area, then you could eventually send a pm to get that name (I wouldn't give it) but if not, then its unhealthy curiosity, and a desire to  burn the witch.

There are no Borg. All resistance is fertile.